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'1 ,3 1 4,6 1 1 l Patented Sept. 2, 1919.

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FRANK RICHARDSON STAFFORD, 0F PHILADELPHIA, PENNSYLVANIA.

DIE.

Specification of Letters Patent.

Patented Sept. 2, 1919.

Application mea August 22, 191e. seriai N. 116,346.

To all whom 'it may cof/wem: Be it known that I, FRANK RICHARDso STAFFORD, a citizen of the United States of America, residing at Philadelphia, in the county of Philadephia and State of Pennsylvania, have invented certain new and useful Improvements in Dies, of which the following is a specification, reference being had therein'to the accompanying drawing My invention relates to dies. It has for its object the attainment of certain improvements in dies as aproduct and as tools. The objects may be briefly stated as follows: (l) The formation of the working dies as separate units interchangeably mounted on a body to be held in a press or otherwise; (2) the production of such unit dies by means of master dies, with mathematical precision so that they are not only perfectly interchangeable, but also capable of duplication individually; (3) the holding of the said dies in working position on thetbody or bodies vautomatically with perfectprecision; (4) the construction and arrangement of both master dies and the working dies so as to insure long life and lack of strain in use. Ancillary features of the invention and improvement will sufficiently appear from the detailed statement hereinafter.

My invention is illustrated in the accompanying drawings in which- Figure 1 is a plan view showing a set of three unit dies mounted in working position on a body or holder.

Fig. 2 is a longitudinal section of Fig. 1 on the line 2-2 thereof.

Fig. 3 is a plan view of a master die for forming the unit dies of Figs. 1 and 2. It also represents the hub punch or duplicate of the master for the same purpose.

`Fig. 4 is a section on the line 4-4 of 'Fig 3.

Fig. 5 is a plan view showing a trimming die and holder for trimming the outside of the article. y

Fig. 6 is a cross section onthe line 6-6 of Fig. 5.

Figs. 7, 8 and 9 are sectional views showing three lstages in the formation ofthe trimming ydie of Figs. 5 and 6.

Fig. lOis a perspective view of the article to be produced by the tools of the preceding figures.` 1'

' Referring to Figs. 1 and 2, l indicates the body for the Working dies, which has its upper `surface 52, and may have its other "surfaces, machined, hardened and ground perfectly true.` Resting upon the surface 2 arethe unit dies 3, 4 and 5, each of which has a broad base 'and beveled sides, and has its base and top preferably ground both before and after hardening, `and its beveled sides made perfectly true, in a manner to be presented explained. Each Aof these dies has in its top or` crown a sunken impression `of one half or side of the article shown in 5., The impression in die 3, by which the first operation is performed, is somewhat rounded so as to cause the metal being worked to flow properly into form. The die 4 has the impression sharp for fully forming the article, without trimming the flash from the outside edges, except such as are of considerable thickness or mass, as for example the ends of the part marked 6 in Fig. 1'0. The die 5 has I,the same sharp impression as the die 4, but outside of this impression the metal of the die is cut away or shaped so as to produce sharp edges, as indicated at 7 in Fig. 2, for the purpose of trimming off superfluous metal from the article, so far as possible.

It will be understood that the article shown in Fig. 10 is selected for purposes of illustration only, and that the shape and proportions of each die .may be varied according to its uses, without departing from the invention, The specific form of article and the specific form and arrangement of the set of tools illustrated and described herein, are for drop forging, on hot metal, the particular metal in this case being iron or steel; but certain operations which will be pointed out, are performed when the metal is cold; and by making slight changes which will be apparent to those skilled in the art,4 these tools are perfectly applicable to cold stamping, as required in the manufacture of such articles as jewelry, and many others.

Each of the dies in Figs. 1 and 2 is drilled to receive a dowel pin 8, and all the dies are held in position on the body 1 by a also rilled to receive dowel pins 10, and is securedto the body by bolts 11. The clamp ing plate has an opening fitting over each die, of the same shape in plan as the body of the die, and accurately beveled to t closely against the beveled sides ofthe die, and to hold the latter firmly against the clampling plate 9 which for convenience isV bodysurface 2 when the bolts 11 `are set up.

The complete 'set of tools comprises a pair of assemblages, each member of the pair being identical with' the s'i1igle-w---asseinblage shown in 'Figs 1 and 2, except each other. That is to say the impresl sions in the'dies are ",rights and lefts." vOne member of the pair is secured to the bed plate of the press (notshown'ias by means of :the doveV tail 112, `and thelfother member is secured to the'drop head.' I The Vmethod ofsecuring lthese members formsv no part of the presentv invention, and mayl bervaried laccording `to circumstances, V l y order to make each die interchange-v able, that is to 1say lto make 4perfect duplicates, and also' `tofsi'niplify and render more efliientk their. manufacture1 'prqducathe dies' 3,94 andV 5.orany equivalent form yof working'unit dies Aby means ofh'masterdies illustrated as toene appropriate y,type in Figs.` 3 and 4. ,In these figures, 13 indicates a heavy collar," of steel, having a central opening through it, lwith opposite flaredor beveled entrances 14 and 15, and an.r inter mediate straight sided portion 16. `The flared openings 14 and 15 are of the precise x shape and dimensions of the unit dies 3, 4

and 5, and the central openingV 16 has `the same vlateral dimensions and shape as the top` orcrownof each die. In the opening 16 isI fitted withadriving fit, a hub of-a master 11. tool17, whichalso includes a part 19, the

parts 17 and 19 being,secured .together by the pin 18. This assemblage constitutesthe master tool. l One part of,l this tooll part19 (seelig. 3) has the sameeontour as the ar-A ticle of Fig.10,;in-plan. This .partb19is maderfrom `a bar of steel planed to lshape and' isU then driven ,into Aa corresponding opening in the collar 13 and secured by the pin 18. 'The vupper and lowerfaces, 2O and k 21,offthe part 19,A are formed to :reproduce theopposite halves Aofithe .shape off the article. n v

As will hereafter appear, the working dies 3 and 8a of a pair such as-shown in Fig. 4 are v formed by forcingthem toward each other into the I beveled; entrances 14 and v `v15, f by which ytheir faces receive sunken ,impressions fromy the projections 20and 21, andl their sides aresimultane'ously formed with a perfect and accurate bevel.

vl.The operation lis ias follows:I i Y I Having thexarticle, or a sample thereof, or drawings, lthe rst step vis'to make" the collar 13 andthe master punch including the hub ,Y 17., Thelatteris madef.preferably'in two partsr'. e. the punch 19 .andfthe hub.,17,.as shown'in, Figs. 3 and 4fand.heretofore def scribedq A. pair of: blanks Bandwhich havel been first: shaped, which lInray'be done by l drop forging themhot, andremovingthe scale, are inserted inthe entrances 14 and then placed in avhydraulic press and sub# Jected to very heavy pressure. By this means, Ythe blanks-3 Vand 3a /re'ceive in their faces impressions from the opposite punch that they are necessarily complements of' cisely beveled by the beveled sides 14-15 of the collar. When properly groundband f, hardened, these two parts Sand 3a may then vfaces 20 and 21 and also have sides prebe filed away as perfect master dies.

In the further practice of, l` my invention, the punch including the hub 17 is removed andasolid metal blank (not shown) put in its place. The master dies` 3 anda are then placed in position, and the assemblage I is again subjected to heavy pressure inthe hydraulic press. The4 result 'is the formation from the solid blank of a solidj hubpunchconstituting a perfect replica of thel two-part master punch including the hub 17.

This solid metalblank punch is Ithen hardened and left in the collar 13 for use in producing theworkingdies, 4.or 5. By repeated operations as many of these working dies may then bel` produced as desired, the blanks `Sand 3a typifying the cold. metal blankswhich are struck up into perfect dies, bothaas to theirzimpressions and theirccoiiif. tours, ready -foraise asv shown in Figs. 1 and 2.

AItis to benoted that the method iofclaimp i ing `the trimming die in place shown inFigs.. 5 and 6 is essentially the sameas ythat illus-I trated in Figs. 1 and 2. `y' Lconsider myself the original andI first inventor of this con# struction of clamping and centering and shall claim the same andthe apparatus therefor broadly hereinafter.

It should also be noted that acharacteris-,j tiefeature of this invention'liesjinthesimultaneous pressing ofopposite blanks against thel opposite working faces of a I master punch, as. shown in Fig. 4, lwhereby the holder and other parts arerelievedofv strain necting it to the bar, and placed betweeny the second. pair of :dies l4. Here the finished shape is imparted to the article by va second blow,y butIit is not trimmedl and the, gate projectiomis left upon it. The openings for this gate projectiony are indicated at -37 in Fig.1.` *After the` second blow, the articleisagainremoved, and forfa thirdoperation is placed between the pair 0f dies. The succeedingblow vvthen -completes ,the surfacefinishjof the article and trims the bulk ofmetal away .fromthe .outer and inner surf faces, leaving nothing but a very thin film in places, and if the dies are new, leaving practically nothing at all. The perfection of this trimming, and the slightness of the Hash left thereafter, depends almost entirely upon the skill of the mechanic who sets up the tools in the press.

Many other modifications and modes of application of this invention might be detailed but -it is thought the foregoing will be sufficient to enable skilled engineers and mechanics to fully receive the benefits flowing from the novel features presented. The principal two of these novel features, are, first, the manufacturing of the working dies as interchangeable units, and their mounting upon a body by bringing together perfeet hardened surfaces, self-centering and self-adjusting, and second, the manufacture of these dies by means of master dies and punches, and particularly the feature of the hub punch making two opposite impressions at one stroke, and with the surrounding collar perfectly and precisely shaping and finishing two complementary dies to form a pair. To those who are familiar with the processes of tool making heretofore practised, it will be at once apparent that with this invention I effect not only vastly better results, making glass finished dies and punches with mathematical precision, and within any degree of accuracy detectable by micrometric measurements; but also effect great economy in the cost of dies. Instead o-f having to cut and mill and grind, and handetool the metal out from the contours or edges of the punch and die, I save all this fine work, with its tedious consumption of time, and at one blow produce a more perfect die or pair of dies, than an expert tool maker could get out in a week.

Having thus described my invention what I claim and desire to secure by Letters Patent is l. A tool of the class described comprising a body, interchangeable unit dies resting uplon said body, and clamping means having an accurately fitted beveled projection surrounding and resting against each die, with means to secure said clamping means to the body.

2. A tool of the class described comprising a body, a die having a base accurately fitted to the surface of the body and having beveled sides, and a clamping plate having a beveled opening surrounding and accurately fitted to the beveled sides of the die, with means for securing said clamping plate to the body.

3. A forming tool comprising the following instrumentalities: a body of considerable mass provided with means to secure it, lnediately or immediately, in a press, and having its working face smooth and true, a die head of relatively small mass having its base accurately ground to fit solidly against the working face of the body, means secured in the body of the die to center the latter in fixed position, and a clamping plate secured upon the body, with an opening to take the die, the walls of said opening being inclined symmetrically with respect to the center, and engaging similarly inclined and accurately registering walls of the die, whereby accuracy, solidity as a unit, and permanency of adjustment, as between the die head and its body, and quick and easy interchangeability of the Working parts of the die are secured.

4. A forming tool, comprising a body portion, a plurality of dies adapted to be arranged upon the body portion and tapering outwardly away from the body portion, al clamping plate provided with a corresponding number of openings which taper outwardly away from the body portion and are adapted to snugly receive the dies, and means to secure the clamping plate to the body portion.

5. A forming tool, comprising a body portion, a plurality of dies adapted to be arranged upon the body portion and tapering outwardly away from the body portion, a clamping plate provided with a corresponding number of openings which taper outwardly away from the body portion and are adapted to snugly receive the dies, separate guide means for the clamping plate carried by the body portion, and means to lock the clamping plate to the body portion.

In testimony whereof I affix my signature.

FRANK RICHARDSON STAFFORD.

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